Process of treating lumber



Patented Sept; 9, 1930 rs A I? it LOUIS comma), or BROOKVILLE, INDIANA rnoonss or TREATING LU BER This invention relates to a process for treating lumber and more particularly to a process for steaming black Walnut boards.

Blackwalnut boards, as they come from the sawmill 1n the Woods are known as run of the mill boards and are usually of a un1 form thickness and of Varying Widths. Theserun of the mill boards comprise a central longitudinal section, called the heart portion, and a longitudinal section at each side edge bounding the heart portion which is known as the sap portion. Thesap portion appears to be lighter in color and ofa slightly dif-' ferent texture from the heartportion.

whave been unable to determine Whether the these run of the mill boards at thefactories by separating the sap portion from the heart portion and only using the heart portion, thereby necessitating the loss of the sap portion, or in only utilizing it in inferior grades of furniture and building trim. The foregoing practice is not only extravagant but it precludes the use of the entire Width of the run of the mill boards. v r V The primary object of this invention is to )rovide in a manner as hereinafter set forth p a 1 for simultaneously abstracting or dev1tal1zing the harmful elements in the sap portion and uniformly coloring run of the mill black.

Walnut boards.

Another object of the invention is to pro vide in a manner as hereinafter set forth, for producing a black Walnut board Which will not Warp, crack or absorb moisture in the finished state; and Which is capable of being polished or finished so as to present a uniform color and texture throughout when used in the manufacture of furniture or building trim.

Further objects of the invention are to provide, in a manner as hereinafter set forth, a process which is economically carried on in the heart Application filed December 11, 1928. Serial No. 825,393.

Without danger of injuring the lumber; which does not require the use of expensive equipment or skilled labor and moreover does not utilize any chemicalsor dyes in its operation. g

In carrying out the invention, a suitable vat or treating receptacle of anydesired ma;

terial such as Wood, cement or metal is utilined. The shape of the vatis preferably square and is provided With a suitable drain to Withdraw the products'of condensation accumulating therein. In the bottom of the v lSlGCf-Jiltitl a series of perforatedpipes or individual jets as desired and said pipes or jets are connected to the steam supply pipes.

It has been found that et, heavy or ex haust steam is preferable for the purpose of this inventionpbut the processtvvill operate successfully with any kind ofsteam. Itis not necessary nor advisable that the vat be pressure tight and it may be open at the top or may be provided with loose fitting cover.

There Willhe no. abnormal pressures developed 1n the "vat'and t 1s wlthln the contemplation of the IHVGHJEIOII to treat the lumber at atmospheric pressure; A suitable support is secured to the bottom of the tank so as to provide'a resting place for the lumber which is spaced from the steam jets in the bottom of the vat. The space will be filled with steamduring the treatment'of the lumber. The run of the millboards are piled in layers; one on top of the other and all of the boards will extend in the same direction. The boards are so arranged that the sap per tion of each board in eachlayer will abut against andbe adjacentto the heart portion of the boards in the overlying and the underlying layer. The varying Widths of the run of the mill boards will accommodate the ar rangement and moreover, will provide for spaces between the edges of each of the boards in the same layer, so as to compene satefor the lateralexpansion Without altering the relative positionvwith respect to the overlying and underlying layers. \Vhen the Vat has been filled With the boards the entire mass is covered with black Walnut saw dust and he steam is 011 211 e ewe l i? n er ill? vat.

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The steam slowly penetrates the mass of lumber and there will be a marked condensation within and on the surface of the pile of lumber. At the same time the condensed steam will react with the walnut saw dust and the products of the reaction will slowly percolate through the pile of lumber. In a vat 16' x 16 x 8 deep, satisfactory results have been obtained by steaming the charge for 36 hours. The time factor is 'ariable according to the thickness of the boards, the size of the container. the quality of the steam and the seasoning given to the lumber prior to the trcament; and the aforementioned time is only given for the purpose of illustra tion without limiting the invention thereto.

When the boards have been treated the predetermined time the steam is turned off, the saw dust is removed and the boards are taken from the vat. It will be seen that there is a deposit on the surface of the boards where they have been in contact with each other. The corrosion is apparently due to the exudations from thesap portion of the boards. It will be further noted that the heart portion of the board appears to be lighter in color after the steaming, while the sap portion has taken on the same color and appears to be of the same texture as the heart portion. The boards are then dried, either by the natural process or by means of the conventional dry kiln. After the drying operation the boards are run through the planer, which removes the corroded surface and then they are made up into furniture or building trim. Upon the application of the usual finishes and polishes well known to the industry, the entire width of the board will be of a uniform color and will present a homogeneous texture.

It will be apparent from the foregoing description of the process that there are five factor-s functioning simultaneously during the treatment of the lumber, namely :Heat in the presence of a vapor laden. atmosphere; the percolation through the mass of lumber of the products of the reaction between black walnut saw dust and the steam vapor; the surface contact between heart and sap portion of the boards; the lateral diffusion of coloring matter from heart to sap portion in the same board: and the abstraction of elements which in the natural state impart heterogeneity to the boards. There is a sixth factor that ma" have an influence upon the success of the invention and that is the development of the latent pigmentation residing in the sap portion when subjected to the conditions of this process. It is within the contemplation of this process to claim only the cumulative effect of the six aforementioned factors in producing a black walnut board from run of the mill lumber which preients a uniform color and homogeneous texure.

hereto.

LOUIS J. CONRAD. 

